Just right click the "start" button in the lower left corner, then selected in the next menu "Properties", open the Properties window of the taskbar and start menu" if you have Windows XP.
Go to the tab "task Bar" make sure that in the "notification Area" is checked on the "Hide unused icons". This feature allows you to remove the hidden icons that are not used for an extended period of time.
Select "Customize". In the window that appears "customize notifications" tab in "Current items" expand the entire list and select a convenient version of the proposal: hide when inactive (the icon will disappear only if you had not applied to him), always hide (icon will always be hidden) or always show (and, therefore, will be continuously displayed).
Click "OK" and close all Windows. If on your computer you're using Windows Vista, the procedure is to remove the hidden icons will be a little different.
Right-click your mouse on the "start menu", select "Properties".
In the opened window "Properties taskbar and start menu", select the tab "notification Area".
In the "Icons" put a tick on the "Hide unused icons", if there is not, and click "Configure".
Choose in the window "customize notification icons" section "Current elements", and fully expand the list and select the desired item: hide when inactive (the icon will only get in if you had not referred to his program), always hide (icon will always be hidden to the taskbar) or always show (and, therefore, will be continuously displayed in the system tray).
Click "OK" and close all open Windows.
Make sure that the changes in the icons will be more convenient for you.